The Spare Key to My Heart
by Fatalyst
Summary: The Kagamine twins can't get inside, and it's raining, so they take shelter in the car and dry their soaking wet clothes over the heater while they snuggle up in a warm blanket together.


**DISCLAIMER:**  
The following content is the intellectual property of the  
Yamaha Corporation and its respective subsidiaries  
as well as any participating organizations that own  
various designs and concepts that will be featured. The  
Author in no way claims to be a part owner of any of  
the characters that will be portrayed, and writes with  
the full authorization of the ffnet website.

**WARNING:  
**The following content is rated M for Mature, and may  
contain graphical descriptions of mature scenarios  
that viewers may not find suitable. This is a work of  
fiction: Any and all similarities to real life situations is  
purely coincidental.

* * *

_"Even on a cold, rainy night, locked outside of your own  
house, romance can still blossom..."_

* * *

"Cold. Cold. Cold. Cold. Cold. Cold..."

Rin rubbed her bare wrists furiously, wishing she'd had the common sense to keep something a little warmer to cover her in the event of a sudden storm like this. She looked over her shoulder at Len struggling with the keyhole without success. "Hurry up!" she barked, making no effort to conceal her anger.

"I'm... trying, but..." At the sound of a soft snapping, he froze. "...crap."

Len's younger sister heard it immediately and whirled around. "You broke my hairpin, didn't you?"

"Uh... maybe." A sheepish smile was all he could manage.

"Idiot! Let's go back to the car already, I'm soaking wet and you're completely useless on rainy days!"

"Urk...!" He grimaced as he fumbled for the car keys and, together, they trotted through the fierce and windy rain under the scant cover of Len's collared shirt. "Uwah!"

Once inside, Len immediately began undressing in the driver's seat, while Rin looked on flabbergasted. "N-nii-san, what the fuck?"

"If mama could hear you now," Len chided uncaringly, awkwardly rolling down his trousers and pulling them up into his lap. "I don't know about you, but I'm not going to sit here in wet clothes."

Puffing her cheeks, Rin crawled into the backseat, kicking Len intentionally with her ankle as she passed. "Fold the mirrors away! Don't you dare peek!" she commanded. While Len heeded her instructions, he also started the car and opened the heaters.

"It's not like I haven't seen it before." He said it nonchalantly. "Besides, I like big boobs." Rin kicked his seat and grunted angrily. "Like, E cups." She reached around to strangle him, and he fought back playfully, bursting into laughter. Rather than playing along, however, Rin huffed and retreated to her seat. He could hear her opening the rear compartment.

"You're always useless..." she murmured dejectedly, curling up in a thick wool blanket stashed away for times like this. Len frowned.

"Hey, sorry. I was just kidding, y'know?"

"So, how was Sakine-sensei doing earlier."

"I mean it. I mean—I _didn't_ mean it!"

"Yeah."

"Seriously."

"Okay, okay, I get it. Just shut up. You're being noisy."

She was really mad, not to lash out violently like this. He felt a lump rise in his throat, feeling unsafe. But it was Rin, so he was also worried about her. Yet, because of how they were, always so distant, he couldn't figure the right course of action. The heater wasn't kicking in, but he refused to close the vent because it had to warm up sometime. Until then, he would shiver violently, even while suppressing his natural instinct to keep warm. He closed his eyes and pretended to sleep, hoping that he might actually lose consciousness and pass away the tension in cowardly peace. Something soft and warm came over him.

"?"

Rin slid smoothly between the front seats and covered Len with her blanket, scowling as she sat in his lap. Electricity seemed to pass through their damp, bare skin, and he felt her jolt a little as she connected to his cold, wet surface. At least, that was how it felt to him. "You idiot... You'll catch a cold like this."

He blushed, his heart pounding faster. She was wearing lacy black underwear today. That kind of thing was really... He hoped she wouldn't notice his elevated heart rate. _Even though we're brother and sister_, he thought, _I still really_...

"Even though we're brother and sister," she mumbled softly, avoiding his eyes as though she had discerned his thoughts through them. "You can't think to call on me for something like this?"

"I-it's exactly because we're brother and sister that I wouldn't think to call on you for this..."

She sighed. "Yeah, I know..." Inclining her face to his, she kissed him chastely. "Before you wake me up every morning, you kiss me like this and tell me you love me."

"Y-you were awake during those times?" Shock and fear struck him like a wasp.

She shook her head. "Not all of them, anyway. Hey, nii-san..." Rin straddled her brother aggressively and nipped his neck. "I love you."

"Stop...! If you do that, I'll—!"

"Get really hot?" she finished, moaning with a subtle, demanding undertone. "Good... _Oh_, that's what you meant." She grinned devilishly and pressed against the hard mound growing beneath her.

"Rin," the name escaped his mouth like a forbidden word. "Rin, we can't..."

"If you don't like it, then push me away," she whispered.

The rain picked up. The car swayed in the wind. Inside, to conjoined figured shuddered violently as waves of pleasure coursed through them. Len stiffened as Rin's soft, wet core wrapped around his thick, hard shaft, each little bud of her inner walls brushing against his swollen, pulsating head.

"Oh... _god_..." she gasped voicelessly, knitting her eyebrows and squeezing his shoulders for leverage. These blissful sensations were too intense. Self control broke down and she erupted into a flurry of panic stricken heaves. Wild, untamed cries of delight filled the humming automobile.

"Iyah~ Ha—how is it... Uah~ L-Len?" She bore into his submissive gaze sadistically, relishing in her dominance. "I-it's... unh! tight, r-right...? Uah~ B-but it doesn't... Ooh...! it d-doesn't... hurt... Ungh! HAH! FUCK! AM I... H-HAVING AN UAH~ ORGASM? _OHHH, YEAH_~!"

Rin fell forward past Len's neck and choked for breath, shuddering as her fluids erupted from between them. Only her fluids. She smiled weakly and kissed her brother on the cheek. "Mmm... but that's not enough, right? So, let's go until you cum too. It's okay if we don't come together, today. I just want you to feel good, nii-san."

"I love you, Rin," he answered gently, stroking her hair. He said it gently, but there was a primal flame in his eyes. Unlike the electricity shooting through their bodies before, this flame was slow and delicate and complete.

"N-no... not gently, like that...!" She jammed her eyes shut, too weak from climax to resist his iron grip lifting her body and stroking her atop his organ. "Don't do it gently!" she begged, a new wave of orgasmic cries overcoming her. "It's embarrassing! Uhaaaaah~..."

"I love you so much, Rin. I've always loved you, and I'll always love you. I can't prove it now, but I'll definitely prove it for forever."

"Saying whatever you want... Ah~ idiot...!" Her tongue lolled helplessly. He pushed up and kissed her, sucking on it tenderly. "Mmph—! Mmm~"

Slowly, like poisoned blood it consumed her, embracing her and swallowing her completely. Their sweat poured down their bodies faster than the rain could wash its way down the windshield. She felt as though she could feel his beating heart resonating with hers. "L-Len, I'm gonna—"

"Shh!" Len ushered, urgency in his voice. He locked her lips into his and squeezed, communicating with his whole being what he wanted. And she could understand his completely, without needing to hear or feel. Everything was. Together, they experienced a high that neither would ever dream of feeling separately. Tears welled up in her eyes.

"Rin... hey, what's wrong...?" he asked, worriedly. "Did I hurt you?"

"You really are an idiot..." she was laughing and crying. "I'm happy, you dolt."

"...I see." He tried to smile, but in the heat of the moment felt too unlike himself. "This is weird, now..."

"Is that bad?"

"That doesn't really matter."

"Then, can we fuck some more?" She shot him her best puppy expression.

Len blushed furiously. "Am I... your first?" Rin blinked. Then she shoved him playfully.

"Moron. Take responsibility, okay?"

"Ah~ S-stop twitching while it's still coming out."

"Oh~ You like?" She convulsed tortuously, giggling girlishly. "I love you, Len. You're so cute..."

* * *

Miku smiled nervously and tapped the glass with her keys, pretending to not notice how very naked the Kagamine twins were underneath the covers in the back seat. When Len came out with his boxers on and retrieved his clothes from atop the heater vents, she tried to rationalize her conclusions in a different direction.

"It's about time you showed up," he complained, rolling down the window. "We've been out here for two hours."

"Care to explain why you're both cuddling naked in the back?" Miku raised one brow while Len handed Rin her clothes, one by one. She didn't comment on the fact that he handed Rin her own panties without batting an eyelash.

"We got soaked trying to get in," he explained casually, rolling up the windows and opening the car door. "That was some storm, though."

"I told you we should have stayed at the mall," Rin grumbled, fumbling with her messy hair. She met eyes with Len briefly, blushed, and ran into the house without another word.

Miku just sighed and walked in after, Len closing the door behind them. He went upstairs while Miku went into the kitchen to prepare a pot of boiling water. It was already past dinner and she was sure Len and Rin would be really hungry. "Those two are awfully close, all of a sudden," she said to herself, yawning.

* * *

Wordlessly they came together over his bed. She'd already been waiting for him when he'd arrived. He massaged her breasts while she undressed.

"You're gonna do this twice a day, every day, from now on," Rin told him, trying to hide the fact that she was really, really pleased.

Len smiled anxiously. "That's a bit much, don't you think?"

"But nii-san likes E cups, right? If that's the case, I have a long way to go."

"You really believed me when I said that?"

"Not that," she replied dismissively. "It's just that nii-san can't be a lolicon forever. Maybe I should grow out my hair, too...?"

"N-no way!" Len cried desperately. "It's one or the other, big boobs or long hair, but not both!"

"Ow~ That's too hard, nii-san!" Rin winced in pain, then cooed affectionately when he rubbed her nipples apologetically. "By the way, nii-san..."

"Hmm?" He was engrossed in the task of feeling out her deliciously cute front.

"If we were really brother and sister, would you still make love to me?"

"Huh...? Y'mean... we're not?"

"..."

"..."

* * *

"YOU MEAN YOU REALLY DIDN'T KNOW?" Rin's loud shout echoed into the kitchen, causing Miku to cut her finger as she chopped up a spring onion.

"Ii~tetetete... I guess that means he didn't know about it..." She bandaged her finger quickly and went upstairs to check on the twins. Through the walls she could hear their muffled voices.

"Damn it, nii-san, you're too irresponsible..."

"...but, this and that are two completely different. Besides, doesn't that answer your question?"

"H-hey, you're being gentle again! _Nnfhu_~"

Miku groaned and slammed the door open, covering her eyes and barging in. "Can you guys keep the dirty stuff for when nobody can hear you?"

"Huh?" Len looked up from the bed, his boxers properly on while he massaged Rin's bare back. "The hell're you on, Miku?"

"...!" She blushed even further, seeing his bare back and Rin laying so innocently underneath the blanket recieving a massage. "Ah... I just thought that... Umm, n-nevermind." Flustered, she half blindly stumbled through the door and hobbled down the stairs, mumbling to herself about putting the spare key back.

With Miku gone, the twins glanced at one another slyly and resumed their noisy lovemaking.

"That was really mean..."

"You're saying that in this compromising position?"

"It was. I love you, Rin."

"Me too."

"Be serious, hah."

"_Hey~ No fair~_"


End file.
